The subject of the present invention is a longitudinally adjustable base for a ski binding, comprising a rail for mounting on a ski, a row of teeth extending parallel to the axis of the rail, a plate, for carrying a ski-binding element, mounted slidably on the rail and carrying a latch that can be displaced transversely to the rail and is equipped with teeth for engaging selectively in the teeth of the row of teeth in order to immobilize the plate on the rail in a selected position, a lever for entrainment of the latch mounted pivotably on the lower face of the plate, and means for holding the latch in a locked position comprising a shoe connected to the lever by a connecting rod forming a knuckle joint with the lever such that in a locked position the shoe is pressed against a support and the lever is held in a locking position.